CiteSeer is a scientific literature digital library and search engine which automatically crawls and indexes scientific documents in the fields of computer and information science. Since it's inception in 1997 CiteSeer has grown to index over 730,000 documents and serves over 800,000 requests daily, pushing the limits of the current system's capabilities. In addition, CiteSeer's monolithic architecture inconveniences system maintenance and reduces the flexibility of the system in terms of new feature development, algorithm updates, and system interoperability. In this paper, we discuss the problems of the current CiteSeer architecture and propose a new architecture for a next generation CiteSeer application. The new architecture is based on modular web services and pluggable service components. Preliminary results based on a prototype system show the new architecture enhances flexibility, scalability, and performance for CiteSeer. In addition, new services in development for the next generation CiteSeer system are discussed.